JPS5840207A - Hammer drill - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention includes a guide cylinder for a striking mechanism and a guide tube that is housed in a tool holder and is used to transmit rotational motion to a tool inserted into the tool holder. The present invention relates to a hammer drill in which a hammer for transmitting a striking motion is mounted movably in the axial direction within a guide tube.

Hammer drills, ie, drilling machines that impart rotational and percussive motion to the tool, are widely used today in the construction and equipment industries. For example, striking mechanisms that operate according to aerodynamic principles have become widespread due to the advantages of high drilling performance and low required thrust forces. Such percussion mechanisms usually reciprocate an excitation piston driven by a conventional electric motor and transmit this reciprocating motion via an air cushion to a freely movable piston. In this respect, the excitation piston and the freely movable screw F can be arranged directly one after the other in a common guide cylinder. Furthermore, it is known to design excitation pistons according to the so-called plunger piston principle as freely interlockable piston guides. In this case, the excitation piston and the freely movable screw cylinder are telescopically fitted to each other and are mounted in - guide cylinders. By doing so, the drill can be made shorter in the axial direction. By adopting two types of construction, the guide cylinder can be rotatable or fixed. In the case of a fixed guide cylinder, the rotation is transmitted to the guide tube via an intermediate shaft or a pinion shaft. In order to perform axial movement, the intermediate shaft is installed with some play in the radial direction, but the play itself is large, and since the tool must perform two types of movement, the play is even larger during use. Become.

As a result of this radial play, correct rotation of the intermediate shaft or tool, respectively, could not be sufficiently guaranteed in certain machining operations, such as spot drilling, respectively.

Still other known hammer drills provide separate rams for transmitting rotational and percussive movements. To achieve this purpose, the intermediate shaft is formed hollow so that it does not move in the axial direction during operation.

The guide tube is attached to the inside so that it can be displaced. Since the guide tubes rotate without meeting each other, the radial play is /X! This is largely offset by the precise fit of the However, in this known hammer drill, the tool holder arranged in the guide tube has a tailored tool receiving diameter. Therefore, with this hammer drill, only tools having an insertion end equal to the tool accommodation diameter of the tool holder can be used. Constant insertion and removal of the tool causes considerable wear on the tool holder, while also increasing the diameter of the tool holder, resulting in significant radial play of the tool, making it impossible to actuate the tool accurately for certain applications.

For tools whose drilling function performs its original role without performing a striking motion or striking, the diameter of the insertion end is the diameter of the hole to be drilled. be equivalent to. Until now, in order to accommodate such tools in a hammer drill, it has only been known to insert a drill chuck into a tool holder, the diameter of which can be adjusted to accommodate the tool. When housing a drill chuck in a tool holder, the radial play that further increases with use due to the wear described above cannot be avoided, so even with this housing method, accurate rotation of the tool cannot be avoided. Not guaranteed.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide, in the case of the hammer drill mentioned above, a storage device which allows the tool to be rotated properly or concentrically.

The present invention solves this problem by means of a tool holder with a radially adjustable guide area.

The adjustable guide area ensures that the insertion end of the inserted tool can always be adapted. For example, ranges of tools with the same type of insertion end but each with a specific diameter can also be adapted step by step. on the other hand.

The guide area can be adjusted steplessly.

This has the advantage that tools with any desired insertion end diameter can be accommodated within the adjustment range. Furthermore, the stepless adjustment makes it possible to compensate for manufacturing tolerances or tolerances resulting from wear phenomena. If required, the radially adjustable guide area can also be designed differently. In its simplest form, it may be a pair of pliers (or a collet) or, for example, a bushing with a longitudinal slot. Of course, the adjustment range of such a guide area is small. For free adjustment, it is therefore advantageous for the guide area to be formed with radially adjustable clamping jaws. that time.

Two, eight or more clamping jaws can be provided.

When centering the tool, it is advantageous to provide eight clamping jaws due to the known "intrinsically" stable eight-point support principle. It is therefore possible to accommodate not only tools with a circular cross-section, but also tools with, for example, polygonal, in particular hexagonal, insertion ends.

The radially adjustable clamping jaws center the tool and provide a secure friction lock. In this way, tools with virtually any insertion end can be accommodated within the predefined adjustment area.

For radial adjustment of the clamping jaws, an axially movable cone-shaped sleeve is preferably provided which supports the clamping jaws externally. As a result of the radial movement of the cone-shaped sleeve, all the clamping jaws move radially inward or outward simultaneously.

The clamping jaws thus clamp the tool in the coaxial region of the insertion end 1 on which the hammer acts.

When the hammer hits the rear end of the shank of the tool, the tool is accelerated in the drilling direction. If the tool is not held firmly enough by the clamping jaws, the tool will fly out of the area of the clamping jaws. To prevent this, it is preferable that the lateral front end of the hammer in the drilling direction acts on the clamping jaw.The hammer therefore acts simultaneously on the clamping jaw and the insertion end of the tool. When moved, the clamping jaws supported by the cone-shaped sleeve are pressed radially inward and thus towards or towards the tool insertion end.

As a result, the tool is additionally tightened each time the hammer hits the clamping jaw. The harder the hammer acts on the clamping jaws, the more tightly the tool is also clamped.

The clamping jaws forming the radially adjustable guide area of the tool holder can be arranged differently relative to the guide tube. That is, the clamping jaws can be connected to the guide tube in consideration of the drilling direction and can be arranged so as to protrude in the axial direction. This arrangement of the clamping jaws has manufacturing and maintenance advantages. From the point of view of a hammer drill of compact construction, the clamping jaws can be arranged radially through the guide tube. In both cases, it is advantageous to effect the adjustment of the clamping jaws by means of the axially displaceable cone-shaped sleeves mentioned above. In the first case, the cone sleeve projects radially beyond the guide tube, whereas in the second case it almost radially surrounds the guide tip.

The above-mentioned features allow tools with different insertion ends to be accommodated in the hammer drill in question. Due to the suitable construction, the tool holder can be arranged either on the guide tool or partly on the guide tube, which ensures a sufficiently precise rotation of the tool holder.Adjustable tightening The jaws clamp the tool tightly in the tool holder so as to rotate it with sufficient precision.Differences in concentricity are caused in any case by too large a play in the radial direction of the guide tube.

As mentioned in the introduction, this radial play is reduced by dividing the motion so that only the rotational motion is associated with the guide tube. Therefore, the precise structure for mounting the guide tube in order to ensure sufficiently accurate rotation of the guide tube is another problem to be solved by the present invention.

It is preferable to solve this problem by integrating the guide tube and guide cylinder used to house the striking mechanism. This integral arrangement can prevent deviations from correct rotation or concentricity due to fit gaps or manufacturing tolerances between the guide tube and guide cylinder.

Furthermore, the integral arrangement has the advantage that the support points in the hammer drill housing can be arranged at a greater distance from each other, allowing suitable bearing stresses to be achieved. Furthermore, assembly can be significantly simplified.

In the case of the hammer drill with a radially adjustable guide area according to the invention, an additional concentricity or correct rotation can be improved by arranging the guide tube and the guide cylinder in one piece. From the point of view of the hammer drill usage technology, the integral arrangement of the guide tube and guide cylinder significantly improves the concentricity of the hammer drill required for tool holders without radially adjustable guide areas. Become.

The guide tube and guide cylinder may have the same or different diameters. However, if the outer diameter of the guide tube is smaller than the diameter of the guide cylinder, it not only forms an axial support shoulder but also provides space advantages. In order to provide a compact construction of the hammer and to form an optimal installation situation, the outer diameter of the guide cylinder is preferably 2 to 1.8 times the outer diameter of the guide tube.

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, in a first preferred embodiment the hammer drill has a housing 1. As shown in FIGS. An air percussion mechanism is placed within the housing l.

This striking mechanism consists of a guide cylinder 2 and a driven excitation screw that is installed inside this cylinder 2 and can be displaced in the axial direction).
8 and a freely movable piston 4. The space 6 between the excitation piston 8 and the free piston i acts as an air cushion. The reciprocating motion of the excitation screw 8 is transmitted to the piston noise via the air cushion. Guide cylinder! is integrally connected to a guide tube 6 having a smaller diameter. A guide cylinder 2 and a guide tube 6 are rotatably attached to a housing l via a roller bearing. The roller bearing 7 and the shaft seal 8 are attached in the axial direction of the housing 1 by a retaining ring 9 which prevents contamination from entering the housing l with the shaft seal 8.

A gear 10 is connected to the cylinder 2 so as to rotate together with the guide cylinder 2. A gear 10 is driven by a pinion 11 which is also attached to the housing l.

The hammer 12t is attached to the guide tube 6 so as to be movable in the axial direction. The guide tube 6 has a tool holder at its tip. The chuck body 18, the radially displaceable clamping jaws 14 and the cone-shaped sleeve 16 essentially constitute a tool holder. Here, the cone-shaped sleeve 16 is connected to a threaded portion IB provided on the chuck body 18.
It is coupled to the chuck body 18 by a. Annular spring 16
This forces the clamping jaws 14 radially outwardly against the inner surface of the curved sleeve 15. A chuck body 18 is attached to the guide tube 6 by a tangential link so that it does not rotate or move in the axial direction. The cone-shaped sleeve 15 is attached to the chuck body 18 by the threaded portion 18a.
axially to move the clamping jaws 14 radially inward or outward. In this way, a radially adjustable guiding area is created between the clamping jaws 14. The insertion end 18 of the tool is inserted into this guide area. Insertion end 18
The rear end of the hammer 12 is brought into contact with the front end of the hammer 12.

The impact generated by the screw 4 is transmitted to the insertion end 1B of the tool by the hammer 12. The lateral front end of the hammer 12 in the drilling direction acts on the tightening jaw 14 and the insertion end 1B.

Each time the hammer 12 acts on the clamping jaws 14, the clamping jaws 14 are moved slightly in the drilling direction and are pressed radially inwardly against the insertion end 18 by the cone-shaped sleeve 15.

Therefore, the insertion end 18 is more firmly fixed, thereby preventing the insertion end 18 from popping out of the tool holder or causing knocking. The transmission of the rotary movement to the insertion end 18 of the tool takes place via the guide cylinder 2, the guide chap 1 chuck body 18 and the clamping jaw 14.

The torque is transmitted from the clamping jaws 14 to the insertion end 18 by frictional fastening or forced fastening, respectively.

The direct connection of the radially displaceable clamping jaw 1 as well as the guide tube 6 to the guide cylinder 2, which is integrally mounted on the housing 1, enables precise centering of the insertion end 18 and ensures that the tool is concentric. can be placed in By transmitting the rotational motion and the striking motion separately, the mass to be accelerated by the piston 4 can be reduced, so that high striking performance can be obtained.

As shown in cross-section in FIG. 2, the tool holder comprises eight clamping jaws 14. As a result, the insertion end 1 of the tool
B can be centered accurately. However, it is also possible to provide two or four or more clamping jaws.

A second preferred embodiment of the hammer drill, shown in FIGS. 8 and 4gJ, is substantially identical to the first embodiment shown in FIGS. 1 and 2. Dog, guide tube 26 to guide cylinder 2
2 and extends to the insertion end 28 of the tool. The clamping jaw 24 is made to protrude into the guide tube 26 through the passage opening 26 aTr, and the cone-shaped sleeve R9 bolted to the guide tube 26 is connected to the annular spring 27 .
to press the clamping jaws 24 outward. By axially adjusting the cone-shaped sleeve 29 opposite the guide tube 26, the clamping jaws 24 are moved radially inward or outward. Therefore, similarly the tightening jaws 24
forms a radially adjustable guiding area for the insertion end 1!8. Further, the hammer t6, which is mounted so as to be movable in the axial direction within the guide tube 26, is attached to the tightening jaw 24.
and the insertion end 28 act simultaneously. In this regard,
The additional tightening effect for the hammer drills shown in FIGS. 1 and 2 also occurs for the hammer drills of FIGS. 8 and 4.

[Brief explanation of the drawing]

1 is a partial cross-sectional view of the first preferred embodiment of the hammer drill of the present invention; FIG. 2 is a partial cross-sectional view of the tool holder of the hammer drill shown in FIG.
FIG. 8 is a partial cross-sectional view of the second preferred embodiment of the hammer drill of the present invention; FIG. 4 is a cross-sectional view of the tool holder of the hammer drill shown in FIG. 8;
FIG. 2 is a cross-sectional view taken along IIV-IV. l... Housing t, xr... Guide cylinder 8... Piston for driven excitation 4... Free piston 6... Space 6, 26... Guide tube 7... Roller bearing 8...・Shaft seal 9...Retaining ring 1o...Gear 11...Pinion 12...Hammer 18...
・Chuck body 1J1a...Threaded part 14.24・
... Tightening jaws 16, $19 - ... Cone-shaped sleeves 16, 2?
-...Annular spring 17...Tangential line 1B, R@-
... Tool insertion end 26a ... Passage opening

Claims (1)

[Claims] t. A guide cylinder for a striking mechanism and a tool holder used for accommodating the tool holder and for transmitting rotational motion to a tool inserted into the tool holder. A hammer drill is provided with a guide tube for use in the tool holder, and a hammer for transmitting a striking motion to the worker is mounted so as to be movable in the axial direction within the guide tube, the tool holder having a guide region movable in the radial direction. A hammer drill with the following features. The hammer drill according to claim 1, characterized in that the guide region is formed by a radially movable clamping jaw. a Cone-shaped sleeve, displaceable in the axial direction, supporting the clamping jaw on the outer surface of the clamping jaw in order to move the clamping jaw in the radial direction dI11!1. The hammer drill described in Section 2. Table: Tighten the jaws! The hammer drill according to claim 1 or 3, characterized in that the front end of the side surface in the drilling direction acts. Lay the tightening jaws over the guide tube. The hammer drill according to any one of claims 2 to 4, characterized in that the hammer drill protrudes in the axial direction. Tortoise The hammer drill according to any one of claims 2 to i, wherein the tightening jaws penetrate the guide tube in a radial direction. The hammer drill according to any one of claims 1 to 2, characterized in that the guide tube and the guide cylinder are integrally formed. 1 of the outer diameter. ! 8. The hammer drill according to claim 7, wherein the hammer drill is 1.8 times larger.